An apparatus for supporting a patient in a radiation therapy system is known, for instance, from German Patent Disclosure DE 102 21 180 A1. The apparatus for supporting a patient includes a treatment table that is displaceable in a height-adjustable manner and can also be pivoted about more than one vertical axis. To level the treatment table exactly at the horizontal, a plurality of leveling devices, preferably three of them, are provided that have a wedge that is displaceable by a screw spindle or threaded spindle. The patient located on the leveled treatment table can be positioned, using a so-called laser cross, in such a way that the region to be irradiated is located at the isocenter of the radiation treatment system. The radiation treatment system has a gantry, with an emitter head that is pivotable about a horizontal axis.